Telegraph alarm circuit



Patented May 6, 1939 Unitas STATES PATENT oF-F cE FRED J'. SINGER, OF R-GCKVILLE CENTER, NEW YORK, ASSIGNOR TO AMERICAN TELE- PHONE AND TELEGRAPH GOMQEANY, A CORPORATION OF NEW YORK TELEGRAPH ALARM CIRCUIT Application filed 'April' 24,

This invention relates to telegraph sys tems, and more particularly to systems of the direct current polar type.

The invention provides arrangements whereby the repeater attendants and subscribers at both ends of a direct current telegraph system will be notified in case the line circuit in either direction of transmission goes open, is shortedwith the other line circuit, or is grounded. In the arrangements of this invention, this is accomplished by including at each station in each side of the line circuit a plurality of relay means which will function in the case of line trouble and cause the appparatus at each station to give a break signal. The arrangements of the'invention are particularly useful in connection with one-way polar, four-wire metallic telegraph, and double one-way polar telegraph systems. Further objects and features of the invention will appear. more fully from the detailed description thereof hereinafter given.

The invention maybe more fully understood from the following description, together with the accompanying drawing, in the Figures 1 and 2 of which the invention is illustrated. In Fig. 1 is shown a double one-way polar telegraph system connected for half duplex operation with thearrangenents of the invention associated therewith; Fig. 2 is'a modification of the arrangements ,of Fig. 1. Similar reference characters have been utilized to denote like parts in both of the figures.

As the invention is particularly adapted for use with-a double one-way polar. telegraph system. it has been shown as associated therewith in Fig. 1 when they system is connected for half duplex operation; However, it is pointed out that it might equally well be used with such a system when connected for full duplex operation or for other types of systems. The arrangements of Fig. 1 show atelegraph .line circuit comprising the lines L and L interconnecting stations A and B. At station A there is provided a loop circuit which will include the key K the sounder S the sending relay R and a break relay R The windings of the relays 50 .R and R5 are arranged in the usual balanced 1929. Serial No. 357,747.

relation. The loop circuit is completed overthe contacts, of a receiving relay R and may be connected either to the negative battery 1 or the positive battery 2. Connected to the junctionpoint of the windings of relays R and R is aswitching arrangement controlled .by the-slow operate relay R The operaion of this relay connects the windings of relays R and R directly to battery instead of through the armature and one contact of .relayR to battery. Relay R is controlled 'bycircuit arrangements under control of the relays B and R serially included in line L and relays R and R serially included in line L. At the station B are provided arrangements identical with those at station A. Similar reference characters with the added designation prime have been utilized to denote elements at this station similar to those already described with respect to station A. p g

It is believed that the arrangements of the invention may be more readily understood from the following description of the operation of the double one-way polar systemin half duplex operation as illustratc-zl in Fig. 1. VVhen'the telegraph key K at sta tion A is closed, current of 60 milliamp'eres flows from ground through the, key K sounder S upper windings of relays R and R through the'armature of relay R to 130 volt battery to ground. At the same time another current of 30 milliamperes value flows from. ground through the lower windings of relays R and R through the armature of relay R and through 130 volt battery to ground. This latter current is in a direction to oppose that flowing in the upper windings of relays R and R but is onlyhalf the value, so that armatures of relays B and R are held on their marking contacts; IThe .armatureof relay R being. on its marking contact, closes the line circuit L to l30 volt battery at station A,.a nd therefore current of about 35 milliamperes flows over the line circuit L to station 13, returningv to station A through ground. Thedirection of this current is such that relay R at station E is 'heldon its m arking'contact. Since the armature ofrelayR; is on its markingcoir than the current through the upper wind- IROS, and ca'usesthearmatures of these relays to stay on their marking contacts and also causes tne sounder-S" to be closed. Now let it be assumed that at station the operator opens the keyK Current will stop flowing through theupper windings of relays R and R and the current flowing through the lower windings of these relays vill cause the armatures of these relays to move to their spacing contacts. lVl1en the armature of relay R is on its spacing contact the opposite polarityot battery will be connected to the line L causing the armature oi relay R 1 at station B to operate to lts spacing contact. This operaton connects the same polarity battery on both terminals of the lower windings of relays R and R and therefore no current flows through that circuit which includes the sounder S Sounder S therefore operates tospacing and the spacing signal sent from key K, at station A is received on the sounder S gat'station B.

The operation of R to spacing also reverses the direction of the 30-milliampere current flowing through the upper windings of relays R' and R' so that these relays are held on their marking contacts.

. It is pointed out that regardless of whether the telegraph key K at station A is opened or closed, the relays R andR at station B will remain on their marking contacts because (11) the current through the upper windings of relays R' and R' is equal to 30 milliamperes and opposes the eflect of the milliampere current when the key K at station A is closed and the relay R at station B is on its marking contact, but (2) is reversed and therefore still holds the relay armatures of relays R and R on their respective marking contacts when the key K at station A is opened, although for this condition the armature of the relay R at station E is on its spacing contact and sounder S is open. Therefore, when the operator at station A is sending telegraph signals over line L the current flowing over line L to station A'froin the l30 volt battery at station E and re turning to station B through ground, continues to flow, and relay R at stationA is held on its marking contact.

If the operator at station A is sending and the operator at station B wishes to break him,

theoperator at station B will'open his key K If the operator at station A has his key K open at this time, he will not be aware that a break signal is being sent to him, However, as soon ashe closes his key,'the armature of relay R at station B will move to the marking contact, and since this reverses the current through the upper windings of relays R and R;.,, the armatures of these relays will move to the spacing contacts and current ofopposite polarity will be sent over line L to operate armature of relay R at station A to its spacing contact. hen the armature of relay R operates to its spacing contact, the current through the lower windings of relays R and R will be reversed and the current through the upper windings of these relays will be reduced to zero, due to the fact that the same polarity battery is connected to both ends of these windings. This will cause sounder S to operate to spacing and the operator at station A will knowthat station B has broken him. The operator atv station B can now begin sending, and as soon as he sends, the marking current will continue to flow over line L and hold relay R at station B on its marking contact, as was the case before withrelay B, when the operator at station A was sending to station B.

Let it now be assumed that the line L is broken or opened up when the operator at station A is sending. The current will be removed from relay R at station B, but due to the residual magnetism, its armature is apt to remain on the marking contact. The operator at station B will therefore not know that the line has failed and may not open his key K for some time to find out if there isany trouble. In the meantime, the operator at station A will continue to send, not know ing that theline is broken because his local circuit is under the control of relay R and his telegraph key K and unless the line L has also failed, he will have noindication that station B is not receiving his message.

To prevent the'above conditions from occurring, and to enable the operators at stations A and B to know when line L has opened up, therelays R R B' and B' have been added to the telegraph system.

The action of these'relays in overcoming the above described objection will now be explained. Relays R; and R are connected in series with the line L and as long as the line is closed will remain operated except for a possible kick-off during the time the armature of relay R is moving from its marking and spacing contact and vice versa.

"The armature circuits of relay R and R control the operation of the relays R and R respectively. However, since relays R and R are slow-operating relays, the armatures of relays R and R' must 'rernainreleased for one or two seconds before relays R and R will operate. This situation enables the relays R and R to kick ofifor short intervals of timeduring normal operation of the line circuit without causing reay R8 e R B er ra e- ,How f the. line circuit L is openedfor one second or more, relays R and R are released and relays R and R' are operated until the line closes again. Operation of relay R with relay B on its marking contact, causes the opposite polarity of battery to be connected to the windings of relays R and B and therefore causes the sounder S at station A to be opened, giving the operator at that station an indication thatlineL has failed. At the same time operation of relay R' at station B will reverse the polarity of the battery connected tothe windings of relays B's and B' and open sounder Si, thereby also establishing the break at station B, even though the armature of relay B' may remain on its marking contact, due to residual magnetism in the relay. Both operators are therefore automatically informed that a failure has occurred. lVhen theline L is closed again, relays B and R' will again be energized and theirarmatures will be pulled up, causing relays R and R' to release and restore the circuit to normal again. 7 i 1 If the line L is broken when the operator at station B is sending, the relays R and B' will release and relays R and R' will operate. as heretoforedescribed. When the relays R' operates, the opposite polarity. battery will be connected to the-junction point of the windings of relays B' and RT at station B. This will tell the operator at station E that the circuit between him and station A is broken. At station A the operation of relay R 'will likewise tell the operator, who has been receiving signals from station B that the circuit between'him and station B is broken. Therefore, regardless of whether the operator at station A or the operator at station B is sending and line L is broken, both will receive the break-signal.

Similarly if line L is broken when either operator is sending, the release' of relays RQ and R and the operation thereby of relays R and R' will break the operators at both stations, and when the line L is restore-cl to normal again, relays R; and R will again operate and cause relays R and R' to release and restore the telegraph connections to normal.

Another line trouble that will be taken care of by the alarm circuit arrangements of the invention, is a grounded line. For example, let it be assumed that line L becomes grounded and that the operator at station A is sending atthis time. The armature of relay R will be on its marking or spacing contact. depending on whether he is sending a marking or a spacing signal. In either case battery will be connected to line L and will be flowing through the windings of relays R, and R When the line is grounded, j

this current through relays R and R, will become abnormally large. Relay R; will not be afiected and will remain operated, but relay R will now operate. Relay R is a jand'when a large leakage is present. Operavtion of thls relay will energize'relay R the break signal.

marginal relay and is normally released but designed to operate on a current of a'piedetermined value slightlygre'ater than the line current when the line circuit is. closed which in turn, will'operate and break the operator at station A. Station B will receive the break signal because relay R' connected in the line L, will have the current removed from it, due to the ground in the line and will'therefo-re releaseand operate R' which, inturn, will give the operator at stationB a break signal.

hen the ground is removed from the line circuit L the'respective alarm relays will be restored to n'ormal'and the telegraph circuits between the twostations will also return to normal. Similar results will be obtained it the operator at station B is sending when the line L is grounded. "Furthermore, by means of relaysR B R ,"and R' a break signal is established at both stations if "line L is grounded.

A third line trouble that is taken care of by thearrangements of this invention, is a case of short-circuit between the twolines L and L For example, if lines L and L, are shortcircuited and if the current becomes excess1ve in either end of thecircuit, the relays R and B or relaysRf and R will operate and in turn operate the corresponding relays E cr- R and break the two operators. On. the other 'hand if the current is reduced to zero at either end, relays. R and R or relays B' and R will be released. The'release of these relays will operate the corresponding relays R or B' and also give the operators It is pointed out thatin'the arrangements heretofore described, the relays R and R,,

are normally released and are slow to operate when current is passedthroughthem. The

advantage of this arrangement is that normally no current is drawn trom the batteries supplyi ngthe'windings of these two relays.

The disadvantage lies in the diificulty of obta-ining a. relay which will operate slowly. "Accordingly, an alternative .alarmi clrcuit ar- "rangement 1s illustrated in Fig. 2. In this arrangement, the contacts of relays R R R and R are connected inseries rather than in parallel, and normally, current" flows through the winding of relay R With such an arrangementthe relay B may be made a slow-release relay rather than a slow-operate relay. As the operation of the arrangements in other respects would be substantially similar to that heretofore given, no further-dea scription will be given. v

-While the invention ha'sbeen disclosed as Q embodied in certain specific arrangements wh1ch are deemed desirable, understood that it s capable .ofembodl'mentininiany and other forms and types o tcii'cuits, without de- Earting from thespirit ofthe invention as dened by the appended claims. r

hat is claimedis 1. A telegraph circuit interconnecting two stations of the polar duplex-type, a loop circuit at one of said stations including a sounder and balanced sets of windings of a break rclay and a sending relay, and means responsive to an abnormal current condition in said telegraph circuit for'reversing the polarity of the current connected to the junction point of said sets of relay windings in said loop circuit.

2. A telegraph circuit interconnecting two stations of the polar duplex type, a loop circuit at one of said stations including a souncer and balanced sets of windings of a break relay and a sending relay, switching means for reversing the polarity of the current normally connected to the junction point of said sets of win'dingsin said loop circuit, an alarm circuit for operatingsaid switching means, and relay means in said telegraph circuit for operatingsaid alarm circuitQ 3. A telegraph. circuit interconnecting two stations of the polar duplex type, aloop circuit at one of said stations including a sounder and balanced sets of windings of a break relay and a sending relay, switching means for reversing the polarity of the current normally connected to the junction point of said sets of windings in said loop. 'fcircuit, an alarm circuit for operating said switohingmeans, a relay connected to one ofthe conductors of said telegraph circuit and. operated by the normal flow of current thereover, and means controlled by the release of said relay for operating said alarm circuit. y

at. A telegraph circuit interconnecting two stations of the polar duplex type, a loop circuit at one of said stations including a sounder and balanced sets of windings of a break relay and a sending relay, switching means for reversing the polarity of the current normally connected to the junction point of said sets of windings-in said loop circuit, an alarm circuitfor operating said switching means, a marginal relay connected to one of the conductors of said telegraph circuit and operated, by a flow of current thereover greater than normal, and means controlled by the operation of said relay for operating said alarm circuit. 7 V V r 5. A telegraph circuit intercom'iecting two stations of the polar duplex type, a loop circuit at onset said stations including a sounder and balanced sets of windings of a break relay and a sending relay, slow operate switching means for reversing the polarity of the current normally connected to the junction point of said sets of windings in said loop circuit to operate said sounder as a break signal, andmeans controlled by an abnormal ur n s nd ioain aid t e a h circuit for operating said slow operate switchmg means.

6. A telegraph circuit interconnecting two stations of the polar duplex type, a loop circuit at each of said stations including a sounder and balancedv sets of windings of a break relay 7 and a sending relay, slow operate switching means at each station for reversing the polarity of the currentnormally connected to the junction points of said sets of Windings in each of said loop circuits whereby the sounders therein will operate as break signals, and means controlled by an abnormal current condition in any of the conductors of said telegraph circuit for operating both of saidslow operate switching means. i

7. telegraph circuit interconnecting two stations of the polar duplex type, a loop circuit at one of said stations including a sounder and balanced sets of windings of a break relay and a sending relay, switching means for reversing the polarity of the current normally connected to the junction point of said sets of windings in said loop circuit, an alarm circuit for operating said'switching means, a relay connected to one of the conductors of said telegraph circuit and operated by the normal flowof current thereover, a marginal relay connected to saidlast mentioned one of said conductors of said telegraph circuit and operated by a flow ofcurrent thereover greater than'normal, and'means for completing said alarm circuit over the contacts of said relays.

In testimony whereof, I have signed my name to this specification this 23rd day of April, 1929. r

. FRED J. SINGER. 

